What property of Diphenhydramine makes it contraindicated in the elderly?

The property of Diphenhydramine that makes it contraindicated in the elderly is its anticholinergic effects. Anticholinergic medications can lead to a range of side effects, including cognitive decline, confusion, and increased risk of falls, which are particularly concerning in the elderly population. This age group often has increased sensitivity to these medication effects and may already present with baseline cognitive impairments, making the additional risks posed by anticholinergic properties highly relevant.

While antihistaminic effects are what provide relief from allergic symptoms and sedation is a characteristic of first-generation antihistamines such as Diphenhydramine, these properties alone do not capture the significant concern regarding the elderly. Non-sedating formulations of antihistamines are available, which do not carry the same risks. The classification of opioids does not apply to Diphenhydramine at all, as it is not an opioid medication. Thus, the anticholinergic properties are particularly detrimental for elderly patients, warranting awareness and caution in its use.